115 merc exhaust help

[jakesdog]

I have a 70's or 80's model 115 merc that I just put on my boat. It runs good but when I put it in the lake to let it run when its idling it blows exhaust and spit a little water out where the steering stem comes out of the lower cowling. I don't know if these have a exhaust tube or hose that might be bad or what. I tried to take a look to see what it was, but I don't know where I should start removing stuff to get to it.If anyone has an idea's any help would be great.

 

[Chris1956]

Re: 115 merc exhaust help

Jake, It sounds like the powerhead base gasket has failed, or the casting is rotting out. To replace it, you will need to remove the powerhead and the lower unit. Put it into neutral and drop the LU. Now there are four screws holding the bottom cowling that says "115HP". Now you will have exposed the stainless powerhead mounting bolts. There is about 10 of these including two between the transom bracked and the lower cowling. Now disconnect the control cable linkage, fuel line and electrical, and hoist the 125# block and replace the gasket.

 

[jakesdog]

Re: 115 merc exhaust help

Thanks for the info. I was hoping I wouldn't have to drop the lower, but I need to replace the waterpump anyway. I post my findings when I get it disassembled.

 

[ayuh8]

Re: 115 merc exhaust help

my brother and i just dropped the Lu...on my 115 merc...left it in forward as dir..state...could get it to mate back up bros..moved shifter...all over the place..i moved...a little c.clock wise ..bang..all is good..BUT...i know i have no neutral...she clicks when i spin it ...in any gear...please make this simple...as i read it's just a 45 minute job to change the imnpeller..3 hours and not done right!!!

 

[Chris1956]

Re: 115 merc exhaust help

I recommend that motor be put in neutral when dropping the LU. Use a cresent wrench and carefully turn the shift shaft until it clicks into neutral. Now set the control in neutral. When assembling the motor, you need to turn the flywheel with your hand to align the spline on the driveshaft.

Make sure the plastic insert that aligns the upper shift shaft is installed in the midsection. you may need to rock the throttle handle a bit to line up the shift shaft splines.

 

[jakesdog]

Re: 115 merc exhaust help

Well I finally tore into the motor and it turned out to be the motor mounts. They were almost completely burned out. I've got a pair ordered and should be back in business.

 

[frozenokie]

Re: 115 merc exhaust help

Hey jakesdog - I just got through doing that same thing to this 1986 115. My suggestion to check the lower motor mounts also if you already haven't. It's alot of work to go through and not change them both while you're in there.

Good luck